This invention discloses a patch module, which is used for making and breaking various connections between the conductors of electrical receptacles.
The invention is particularly useful in the fields of computers and telecommunications. A computer is typically connected to a modem, which permits the computer to transmit and receive data through ordinary telephone lines. The cables used in the computer industry usually have 25 conductors, and these cables are connected to suitable plugs, which are inserted into appropriate receptacles. It is often necessary, for diagnostic purposes, or for other reasons, to break the connection between the computer and the modem, and to connect a new modem to the computer, or vice versa. A patching module, such as the one disclosed herein, will make and break these connections as required, while minimizing unnecessary plugging and unplugging of equipment.
One example of a patching device of the prior art is shown in U.S. Pat. No. 4,037,186, the disclosure of which is incorporated by reference herein. In the patented device, the conductors of a pair of receptacles are normally connected together by the wiring configuration on a printed circuit board, and by the action of a slidable panel, mounted for movement along the board. The panel contains a plurality of magnets which, when brought into proximity with small reed switches on the board, cause those switches to close, and the switches then complete the desired electrical connections.
The panel, in the cited patent, is spring-biased so that as long as a patching plug has not been inserted into the device, the first pair of receptacles remain connected together. But when a plug is inserted into the patch receptacle, the plug pushes against the panel, and causes the panel to slide, breaking the connection between the normally-connected conductors. The patch receptacle is connected to one of the first pair of receptacles. Thus, the patented patch module allows the user to "patch" a piece of equipment to one or the other of a pair of devices, while simultaneously breaking the connection between those devices.
Another example of a patch module is given in U.S. Pat. No. 4,154,994, the disclosure of which is also incorporated by reference herein. The patch module in the latter patent performs a similar function to that of the patent cited earlier, but uses a different structure for making and breaking the connections.
Still another patch module is shown in U.S. Pat. No. 4,363,941. The latter patent shows a patch structure intended to reduce the wear on the contacts. The disclosure of this patent is also incorporated by reference herein.
In U.S. Pat. No. 4,037,186, cited above, there is relatively little friction between the sliding panel and the printed circuit board. This is because the connections are completed by the magnetically operated switches, and the magnets need not touch the connections on the board. Since there is very little contact between the panel and the board, the panel slides very easily, and the force needed to insert the plug is relatively low. However, there are disadvantages in using magnetic switches. Not only do they add to the complexity of the device, but they are also subject to interference from stray magnetic fields.
If the magnetic switches of U.S. Pat. No. 4,037,186 are replaced by ordinary contacts, then the friction between the panel and the circuit board becomes much greater. It then becomes necessary to use more force in inserting the plug, and it is also necessary to use a heavier spring. In the devices of the prior art, the plug is inserted in such a manner that it pushes directly against the panel.
It is important not only that the plug be easily inserted into its socket, but also that the plug remain in the socket until pulled out. In devices of the prior art which use a heavy spring that pushes the panel directly against the plug, it is necessary to use a rugged latching mechanism to retain the plug in the socket.
The present invention provides an improved patch module wherein a patching plug can be inserted with relatively little effort. In effect, the plug has a mechanical advantage, against the force of the sliding panel. The present invention also needs only the simplest of latching devices to insure that the plug remains in its socket. The patch module of the present invention is therefore simpler to construct, and more reliable in operation, than the patch devices of the prior art.